Experimental investigation of transition from Fowler-Nordheim field emission to space-charge-limited flows in a nanogap

摘要

An experimental investigation of the transition from Fowler-Nordheim (FN) field emission to space-charge-limited (SCL) flows in a nanogap is presented. Electrodes with gap size D ～ 30-70 nm corresponding to D/λ_o up to a maximum of ～2 × 10～3, where λ_o is the de Broglie wavelength of the space-charge-electrons, are experimented. The transition from the FN field emission to the classical SCL flow is a function of the applied bias and lies in the range 5-15 V. The equilibrium transmitted current density for the 50 nm sample indicates a transition from the FN to the quantum SCL flow at ～0.4 V with D/λ_o of ～35 and then gradually to the classical SCL behavior as the voltage is increased beyond ～9 V. The experiments indicate no sharp demarcation between the different regimes.